Patent GB-1487973-A (GB)
Title: Grinding machine
IPC: B24B49/10
Filed: 1975-01-24
Abstract: 1487973 Grinding CINCINNATI MILACRON-HEALD CORP 24 Jan 1975 [8 March 1974] 3230/75 Heading B3D  A grinding machine for finishing the surface of revolution of a workpiece 16 comprises a workpiece 12 and wheelhead 13 for supporting a workpiece 16 and abrasive wheel 18, respectively, on a base 11, a dressing apparatus 24, control means bring about relative movement between the wheelhead and workpiece longitudinally and transversely of the axis of the surface of revolution to produce a grinding cycle between the wheel and workpiece, the cycle consisting of a rough grind a dress, and a finish grind, means connected to the control means to determine a point of termination of the rough grind when the surfaces reaches a predetermined size, and means measuring the distance from a predetermined point to the point of termination of the rough grind, backing the wheel that same distance for the dressing operation, and later returning the wheel that same distance minus a present distance, so that the finish grind can start without loss of time and without striking the workpiece prematurely. A control box 14 is mounted at the rear of the base 11 and carries a main control panel 19 and a workhead and wheelhead control panel 21. A feed box 22 and table control box are located at the front of the machine. A gauge apparatus 15 is mounted adjacent the workhead, and the dresser 24 is disposed between the wheelhead and workhead. The feed box 22 houses a stepping motor for driving a worm engaging a worm gear connected to a shaft for the slidably mounted table on which the wheelhead is mounted to effect transverse relative movement between the abrasive wheel 18 and workpiece 16. Initially the wheel 18 is retracted from the workpiece to a zero line, Fig. 11, and as the grinding cycle begins the wheel is advanced with controlled force to effect a rought grind, which is a movement through the air and into the workpiece, to point A at which point a memory circuit starts to count the pulses supplied to the stepping motor until the grinding wheel reaches a first size point B, the movement between A and B being at a controlled rate. At point B, the pulses are reversed and the same number of pulses are memorized between A and B is supplied to the stepping motor to reverse the wheel through a distance Y back to point A, the wheel also being reversed to distance X, which is a fixed distance back to the zero line. The wheel is retracted from the bore of the workpiece and advanced a compensation amount to point E and the wheel dressed by the device 24, the wheel then being returned into the bore and advanced the fixed distance X to the point E. A number of pulses and then supplied to the stepping motor 87 to advance the wheel to point H, which number is equal to the number previously memorized minus a number set at a retraction switch to allow for straightening of the grinding wheel spindle which was bent due to the force of grinding when it reached the point B. With the proper selection of the number of pulses, the wheel, when it reaches point H, engages the workpiece and commences to slow advance to the finished ground size at point I.